Optical Eye Toaster

My toaster (and most others I know) has various settings depending on how well-done you like your toast. These settings seem to range from not done at all to 146% cremated. There doesn't seem to be an in-between on my toaster... and that's just for a couple of slices of bread. Heaven help you if you want to toast a few slices, maybe some brown bread, some white bread, a couple of thicker slices, and some frozen bread too.

By "watching" the toast, the toaster could cut itself off and eject the toast when it reached a certain colour - that way, all your toast would come out to your liking, regardless of thickness of bread, temperature of bread/toaster at start of process, etc.

The colour of your toast could perhaps be calibrated when you purchase the toaster? Or you could re-set it as your tastes change - or indeed you could have 4 or 5 settings, so each member of the family can have their toast the way they like it. For calibration, you could simply read off a colour chart - or for more precise control, perhaps you could toast a slice of bread under the grill to just the way you like it, and then show this to the toaster in "read" mode (although that's possibly taking the whole toast thing to a slightly extreme degree).